Apertured webs are utilized in a wide variety of industrial and consumer products. For example, apertured films or apertured nonwovens are known for use in disposable absorbent articles such as disposable diapers and feminine hygiene articles such as sanitary napkins, and the like. Such articles typically have a fluid pervious topsheet, a fluid impervious backsheet, and an absorbent core disposed between the topsheet and the backsheet.
Methods of making apertured nonwoven webs for use as topsheets in disposable absorbent articles are known. For example, U.S. Pat. No. 5,628,097, issued to Benson et al. on May 13, 1997, discloses a method of making weakened melt stabilized locations that are subsequently ruptured by a tensioning force to produce apertures. Other methods, such as slitting and stretching, hot pin aperturing are likewise well known in the art.
Methods for making perforated polymer films are also known. For example, U.S. Pat. No. 2,748,863 discloses the use of a perforating cylinder studded with hot pins arranged in annular rows and an anvil roller having grooves that cooperate with the pins in defining a nip wherein thermoplastic films can be perforated. However, such processes are not disclosed as making three-dimensional apertured webs beyond that of simple material displacement such as an annular ring round the perforations.
When used in feminine hygiene articles as a topsheet (or secondary topsheet, as is known in the art of feminine hygiene articles), three-dimensional formed film apertured webs can have improved functionality because the three-dimensionality provides a degree of “stand off” between the users body and an underlying absorbent core component. Various methods of making three-dimensional formed film apertured webs for use as topsheets are known. For example, vacuum forming methods are utilized to make macroscopically expanded, three dimensional, apertured polymeric webs are disclosed in U.S. Pat. No. 4,342,314 issued to Radel et al. on Aug. 3, 1982 and U.S. Pat. No. 4,463,045 issued to Ahr et al. on Jul. 31, 1984.
Other methods for making three-dimensional formed film apertured webs are known, such as hydroforming as disclosed in U.S. Pat. No. 4,609,518, issued Sep. 2, 1986, U.S. Pat. No. 4,629,643, issued Dec. 16, 1986, and U.S. Pat. No. 4,695,422, issued Sep. 22, 1987, all in the name of Curro et al.
Whether using vacuum as disclosed in Radel et al. or Ahr et al., or hydroforming as disclosed in Curro et al., current processes for making apertured webs, particularly apertured three-dimensional formed film webs, are relatively expensive due to the energy-intensive processes and the capital expenditures necessary for carrying out such processes. Further, for use in disposable articles, the webs cannot be manufactured as part of the process for manufacturing the disposable article. Typically such webs are made in a separate process and stored as roll stock that can tend to destroy or diminish the original three-dimensionality of the web.
Accordingly, there is a need for a less costly method for making apertured webs, including three-dimensional apertured formed film webs.
Further, there is a need for a method and apparatus for making apertured webs that can be incorporated into manufacturing lines for disposable articles, such that the webs need not be stored as roll stock after manufacture.
Further, there is a need for a method and apparatus for making three-dimensional apertured webs that does not require energy-intensive vacuum and/or hydroforming steps.
Further, there is a need for a method and apparatus for making three-dimensional formed film apertured webs suitable for use as a topsheet in a disposable absorbent article, wherein the method and apparatus do not require vacuum or fluid pressure to form the three-dimensional apertures.